Wire for telephones



D. BROOKS. Wire for Telephones].

No. 238,195. Patente d Feb. 22, 1881.

N. PETES, PHOTO'LITHOGRAPHER WASH hGTOm u c UNITED STATES PATENT OFFICEQDAVID BROOKS, OF PHILADELPHIA, PENNSYLVANIA.

WIRE FOR TELEPHONES.

SPECIFICATION forming part of Letters Patent No. 238,195, dated February22, 1881.

Application filed March 4, 1878.

two wires may be arranged in carrying out my invention, and Fig. 2 amodified arrangement of wires.

The objects of my invention are to obviate the disturbing effects ofinduction upon telephone-wires, or telegraph -wires when usedtelephonically, to prevent the same from being affected or influenced byelectrical vibrations or disturbances, and to prevent signals orelectrical currents from being transmitted from a telegraph-wire to anadjacent telephonewire.

In telephonic apparatus, as usually constructed, with one wire andterminal earth-connections, disturbing inductive influences cause atremulous noise or confused patter of sounds, and prevent thetelephone-tones from being clearly transmitted and distinctly heard. Toremove thesedisadvan tages I substitute a metallic return-circuit forthe present earth-terminal arrangement by connecting to thetelephonewire A, or to the telegraph-wire when used telephonically, anadditional metallic wire, B, which runs parallel therewith and in closeproximity thereto, but is suitably insulated therefrom, the wires beingconnected at each end to complete the metallic circuit. The proX- imityof the two telephone-wires to each other is such with reference toneighboring wires, which might cause disturbance in thetelephone-circuit, that such disturbing inductive effects will beneutralized, or, in other words, the inductive eifects in one wire willbe counteracted by the inductive effects produced in the other wireofthis telephone-circuit. Hence the telephonic tones will be clearlytransmitted and distinctly heard, since they are free from disturbanceby the said causes.

\Vhile the two wires should be parallelthat is, should be equidistant,or nearly so, from each other at all points along the lineit should beunderstood that they do not neces sarily run in straight lines, for thetwo insulated wires may be twisted around each other, as shown in Fig.2, for instance.

I claim as my invention The combination of a telephone-wire with anadditional metallic wire running parallel with the said telephone-wireand in close proximity thereto, but insulated therefrom, the wires beingconnected at each end to complete the metallic circuit, allsubstantially as set forth.

In testimony whereofI have signed my name to this specification in thepresence of two subscribing witnesses.

DAVlD BROOKS.

Witnesses:

BRISTOW HUNT, CHAS. AUBREY DAY.

